Galaxy alignments: Observations and impact on cosmology

Abstract

Galaxy shapes are not randomly oriented, rather they are statistically aligned in a way that can depend on formation environment, history and galaxy type. Studying the alignment of galaxies can therefore deliver important information about the physics of galaxy formation and evolution as well as the growth of structure in the Universe. In this review paper we summarise key measurements of galaxy alignments, divided by galaxy type, scale and environment. We also cover the statistics and formalism necessary to understand the observations in the literature. With the emergence of weak gravitational lensing as a precision probe of cosmology, galaxy alignments have taken on an added importance because they can mimic cosmic shear, the effect of gravitational lensing by large-scale structure on observed galaxy shapes. This makes galaxy alignments, commonly referred to as intrinsic alignments, an important systematic effect in weak lensing studies. We quantify the impact of intrinsic alignments on cosmic shear surveys and finish by reviewing practical mitigation techniques which attempt to remove contamination by intrinsic alignments.

52 pages excl. references, 16 figures; minor changes to match version published in Space Science Reviews; part of a topical volume on galaxy alignments, with companion papers arXiv:1504.05456 and arXiv:1504.05546

References in corpus (55)

• The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III
• The Cosmic Evolution Survey (COSMOS) -- Overview
• Wide-Field InfrarRed Survey Telescope-Astrophysics Focused Telescope Assets WFIRST-AFTA 2015 Report
• Galaxy Groups in the SDSS DR4: I. The Catalogue and Basic Properties
• A Vast Thin Plane of Co-rotating Dwarf Galaxies Orbiting the Andromeda Galaxy
• Dark energy constraints from cosmic shear power spectra: impact of intrinsic alignments on photometric redshift requirements
• The Canadian Cluster Comparison Project: detailed study of systematics and updated weak lensing masses
• The Shear TEsting Programme 2: Factors affecting high precision weak lensing analyses
• Cosmology with Weak Lensing Surveys
• A GMBCG Galaxy Cluster Catalog of 55,424 Rich Clusters from SDSS DR7
• The Evolution of Dark Matter Halo Properties in Clusters, Filaments, Sheets and Voids
• Intrinsic galaxy alignments from the 2SLAQ and SDSS surveys: luminosity and redshift scalings and implications for weak lensing surveys
• Constraints on intrinsic alignment contamination of weak lensing surveys using the MegaZ-LRG sample
• Intrinsic alignments of SDSS-III BOSS LOWZ sample galaxies
• Systematic Bias in Cosmic Shear: Beyond the Fisher Matrix
• CFHTLenS: Cosmological constraints from a combination of cosmic shear two-point and three-point correlations
• GREAT3 results I: systematic errors in shear estimation and the impact of real galaxy morphology
• Galaxy alignments: Theory, modelling and simulations
• Image Analysis for Cosmology: Results from the GREAT10 Galaxy Challenge
• Tidal alignment of galaxies
• Means of confusion: how pixel noise affects shear estimates for weak gravitational lensing
• The virialized mass of dark matter haloes
• The Alignments of the Galaxy Spins with the Real-Space Tidal Field Reconstructed from the Two Mass Redshift Survey
• The removal of shear-ellipticity correlations from the cosmic shear signal via nulling techniques
• Three Different Types of Galaxy Alignment within Dark Matter Halos
• Spin alignments of spiral galaxies within the large-scale structure from SDSS DR7
• The alignment of satellite galaxies and cosmic filaments: observations and simulations
• Constraints on the Alignment of Galaxies in Galaxy Clusters from $\sim$14,000 Spectroscopic Members
• Alignment between galaxies and large-scale structure
• Alignment of quasar polarizations with large-scale structures
• Probing the Intrinsic Shape and Alignment of Dark Matter Haloes using SDSS Galaxy Groups
• Intra Cluster Light properties in the CLASH-VLT cluster MACS J1206.2-0847
• Separating intrinsic alignment and galaxy-galaxy lensing
• Characterization and correction of charge-induced pixel shifts in DECam
• Angular distribution of satellite galaxies from the Sloan Digital Sky Survey Data Release 4
• The Anisotropic Distribution of Satellite Galaxies
• Luminous Red Galaxies in Clusters: Central Occupation, Spatial Distributions, and Mis-centering
• A new model to predict weak-lensing peak counts I. Comparison with $N$-body Simulations
• Luminous Satellites of Early-Type Galaxies I: Spatial Distribution
• Galaxy Zoo: Chiral correlation function of galaxy spins
• Dark Matter Halo Models of Stellar Mass-Dependent Galaxy Clustering in PRIMUS+DEEP2 at 0.2<z<1.2
• Constraints and tensions in testing general relativity from Planck and CFHTLenS including intrinsic alignment systematics
• Optical Cluster-Finding with An Adaptive Matched-Filter Technique: Algorithm and Comparison with Simulations
• Alignments of Group Galaxies with Neighboring Groups
• A Technique for Weak Lensing with Velocity Maps: Eliminating Ellipticity Noise in HI Radio Observations
• Alignment of galaxy spins in the vicinity of voids
• Polarization alignments of radio quasars in JVAS/CLASS surveys
• 3D Weak Gravitational Lensing of the CMB and Galaxies
• Weak gravitational lensing with the Square Kilometre Array
• Controlling intrinsic-shear alignment in three-point weak lensing statistics
• Separating weak lensing and intrinsic alignments using radio observations
• Galaxy Orientation and Alignment Effects in the SDSS DR6
• Synergy between the Large Synoptic Survey Telescope and the Square Kilometre Array
• The SKA as a Doorway to Angular Momentum
• Intrinsic alignment boosting: Direct measurement of intrinsic alignments in cosmic shear data

Cited by in corpus (144)

• The Dark Energy Survey: more than dark energy - an overview
• Euclid. I. Overview of the Euclid mission
• Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam first-year data
• Testing General Relativity in Cosmology
• Weak lensing for precision cosmology
• Galaxy alignments: An overview
• Cosmological constraints from cosmic shear two-point correlation functions with HSC survey first-year data
• The first-year shear catalog of the Subaru Hyper Suprime-Cam SSP Survey
• Hyper Suprime-Cam Year 3 Results: Cosmology from Cosmic Shear Power Spectra
• Cosmology from Cosmic Shear with DES Science Verification Data
• Galaxy alignments: Theory, modelling and simulations
• Redshift distributions of galaxies in the DES Science Verification shear catalogue and implications for weak lensing
• Likelihood-free inference with neural compression of DES SV weak lensing map statistics
• Galaxy orientation with the cosmic web across cosmic time
• The halo model as a versatile tool to predict intrinsic alignments
• Cosmic Shear Measurements with DES Science Verification Data
• Dark Energy Survey Year 1 Results: Constraints on Intrinsic Alignments and their Colour Dependence from Galaxy Clustering and Weak Lensing
• Intrinsic alignments of galaxies in the EAGLE and cosmo-OWLS simulations
• Looking through the same lens: shear calibration for LSST, Euclid & WFIRST with stage 4 CMB lensing
• Intrinsic Alignments of Galaxies in the Illustris Simulation
• Cosmic Shear Cosmology Beyond 2-Point Statistics: A Combined Peak Count and Correlation Function Analysis of DES-Y1
• Cosmological discordances II: Hubble constant, Planck and large-scale-structure data sets
• Hierarchical Cosmic Shear Power Spectrum Inference
• Multitracing Anisotropic Non-Gaussianity with Galaxy Shapes
• SKA Weak Lensing I: Cosmological Forecasts and the Power of Radio-Optical Cross-Correlations
• Cosmological discordances: a new measure, marginalization effects, and application to geometry vs growth current data sets
• Intrinsic alignments of BOSS LOWZ galaxies II: Impact of shape measurement methods
• The alignment of galaxy spin with the shear field in observations
• Deep learning dark matter map reconstructions from DES SV weak lensing data
• Neutrino masses and beyond-$\Lambda$CDM cosmology with LSST and future CMB experiments
• Intrinsic alignments of disk and elliptical galaxies in the MassiveBlack-II and Illustris simulations
• Cosmic Shear Covariance Matrix in $w$CDM: Cosmology Matters
• Alignment of galaxies relative to their local environment in SDSS-DR8
• Intrinsic alignments in redMaPPer clusters -- I. Central galaxy alignments and angular segregation of satellites
• Alignment between filaments and galaxy spins from the MaNGA integral-field survey
• The Dark Energy Survey Year 3 and eBOSS: constraining galaxy intrinsic alignments across luminosity and colour space
• Galaxy imaging surveys as spin-sensitive detector for cosmological colliders
• Strong detection of the CMB lensingxgalaxy weak lensingcross-correlation from ACT-DR4,PlanckLegacy and KiDS-1000
• Power spectrum of halo intrinsic alignments in simulations
• Detecting Galaxy-Filament Alignments in the Sloan Digital Sky Survey III
• Caught in the rhythm: how satellites settle into a plane around their central galaxy
• Discrepancies between CFHTLenS cosmic shear & Planck: new physics or systematic effects?
• Cosmological Constraint Precision of the Photometric and Spectroscopic Multi-probe Surveys of China Space Station Telescope (CSST)
• SKA Weak Lensing II: Simulated Performance and Survey Design Considerations
• Unveiling the Intrinsic Alignment of Galaxies with Self-Calibration and DECaLS DR3 data
• The mass dependence of dark matter halo alignments with large-scale structure
• CFHTLenS and RCSLenS Cross-Correlation with Planck Lensing Detected in Fourier and Configuration Space
• SKA Weak Lensing III: Added Value of Multi-Wavelength Synergies for the Mitigation of Systematics
• Observational detection of correlation between galaxy spins and initial conditions
• Cosmology Intertwined: A Review of the Particle Physics, Astrophysics, and Cosmology Associated with the Cosmological Tensions and Anomalies
• Intrinsic alignment of redMaPPer clusters: cluster shape - matter density correlation
• Magnification bias in galaxy surveys with complex sample selection functions
• CosmoGridV1: a simulated $w$CDM theory prediction for map-level cosmological inference
• Scale dependence of galaxy biasing investigated by weak gravitational lensing: An assessment using semi-analytic galaxies and simulated lensing data
• Self-calibration of weak lensing systematic effects using combined two- and three-point statistics
• Intrinsic alignment statistics of density and velocity fields at large scales: Formulation, modeling, and baryon acoustic oscillation features
• Intrinsic alignment contamination to CMB lensing-galaxy weak lensing correlations from tidal torquing
• Euclid: The reduced shear approximation and magnification bias for Stage IV cosmic shear experiments
• Intrinsic Alignment in redMaPPer clusters -- II. Radial alignment of satellites toward cluster centers
• Full-sky ray-tracing simulation of weak lensing using ELUCID simulations: exploring galaxy intrinsic alignment and cosmic shear correlations
• Radio Galaxy Zoo: Cosmological Alignment of Radio Sources
• GAMA+KiDS: Alignment of galaxies in galaxy groups and its dependence on galaxy scale
• Testing tidal alignment models for anisotropic correlations of halo ellipticities with N-body simulations
• Constraints on anisotropic primordial non-Gaussianity from intrinsic alignments of SDSS-III BOSS galaxies
• Investigating scalar-tensor-gravity with statistics of the cosmic large-scale structure
• Increasing the Lensing Figure of Merit through Higher Order Convergence Moments
• Probing the cold magnetized Universe with SPICA-POL (B-BOP)
• GLASS: Generator for Large Scale Structure
• Cross-correlation cosmic shear with the SDSS and VLA FIRST surveys
• Evidence for the alignment of quasar radio polarizations with large quasar group axes
• The dependence of intrinsic alignment of galaxies on wavelength using KiDS and GAMA
• The evolution of galaxy intrinsic alignments in the MassiveBlack II universe
• Luminous red galaxies in the Kilo Degree Survey: selection with broad-band photometry and weak lensing measurements
• Angular ellipticity correlations in a composite alignment model for elliptical and spiral galaxies and inference from weak lensing
• Modeling Intrinsic Galaxy Alignment in the MICE Simulation
• The Subaru FMOS galaxy redshift survey (FastSound). V. Intrinsic alignments of emission line galaxies at $z\sim 1.4$
• Redshift requirements for cosmic shear with intrinsic alignment
• Can intrinsic alignments of elongated low-mass galaxies be used to map the cosmic web at high redshift?
• HYMALAIA: A Hybrid Lagrangian Model for Intrinsic Alignments
• Implications of a wavelength dependent PSF for weak lensing measurements
• Estimating the weak-lensing rotation signal in radio cosmic shear surveys
• First Evidence of Intrinsic Alignments of Red Galaxies at $z>1$: Cross-correlation between CFHTLenS and FastSound Samples
• Beyond Kaiser bias: mildly non-linear two-point statistics of densities in distant spheres
• KiDS-1000: cross-correlation with Planck cosmic microwave background lensing and intrinsic alignment removal with self-calibration
• Revisiting the Galaxy Shape and Spin Alignments with the Large-Scale Tidal Field: An Effective Practical Model
• Almanac: Weak Lensing power spectra and map inference on the masked sphere
• The cross-correlation between 3d cosmic shear and the integrated Sachs-Wolfe effect
• Measuring the scale dependence of intrinsic alignments using multiple shear estimates
• Mapping dark matter on the celestial sphere with weak gravitational lensing
• Photometric redshifts and intrinsic alignments: degeneracies and biases in 3$\times$2pt analysis
• Effects of galaxy intrinsic alignment on weak lensing peak statistics
• Intrinsic and extrinsic correlations of galaxy shapes and sizes in weak lensing data
• Evolution of central galaxy alignments in simulations
• Separating the Intrinsic Alignment Signal and the Lensing Signal using Self-Calibration in Photo-z Surveys with KiDS450 and KV450 Data
• Extracting Spectral Index of Intergalactic Magnetic Field from Radio Polarizations
• Analysis method for 3D power spectrum of projected tensor field with fast estimator and window convolution modelling: an application to intrinsic alignments
• Self-calibration method for II and GI types of intrinsic alignments of galaxies
• A Wide and Deep Exploration of Radio Galaxies with Subaru HSC (WERGS). VI. Distant Filamentary Structures Pointed by High-z Radio Galaxies at z~4
• Toward a Physical Understanding of Galaxy-Halo Alignment
• Galaxy-group (halo) alignments from SDSS DR7 and the ELUCID simulation
• Testing the Impact of Satellite Anisotropy on Large and Small Scale Intrinsic Alignments using Hydrodynamical Simulations
• Mass Dependence of Galaxy-Halo Alignment in LOWZ and CMASS
• Imitating intrinsic alignments: A bias to the CMB lensing-galaxy shape cross-correlation power spectrum induced by the large-scale structure bispectrum
• Revisiting the alignment of radio galaxies in the ELAIS-N1 field
• Intrinsic alignments of bulges and discs
• Combining spectroscopic and photometric surveys using angular cross-correlations III: Galaxy bias and stochastisity
• Three-point intrinsic alignments of dark matter halos in the IllustrisTNG simulation
• Fast likelihood-free inference in the LSS Stage IV era
• The alignment between brightest cluster galaxies and host clusters
• Statistical separation of weak gravitational lensing and intrinsic ellipticities based on galaxy colour information
• A tomographic spherical mass map emulator of the KiDS-1000 survey using conditional generative adversarial networks
• Intrinsic galaxy alignments in the KiDS-1000 bright sample: dependence on colour, luminosity, morphology, and galaxy scale
• Euclid preparation. LIX. Angular power spectra from discrete observations
• Nonlinear redshift space distortion in halo ellipticity correlations: Analytical model and N-body simulations
• Anisotropic correlation functions as tracers of central galaxy alignments in simulations
• Gravitational corrections to light propagation in a perturbed FLRW-universe and corresponding weak lensing spectra
• Third-order intrinsic alignment of SDSS BOSS LOWZ galaxies
• UNIONS: a direct measurement of intrinsic alignment with BOSS/eBOSS spectroscopy
• Optimising LSST Observing Strategy for Weak Lensing Systematics
• A rising tide: Intrinsic alignments since the turn of the millennium
• E/B mode decomposition of HSC-Y1 cosmic shear using COSEBIs: cosmological constraints and comparison with other two-point statistics
• Squeezing Full-Shape Dynamical Dark Energy Constraints with Galaxy Alignments
• Central galaxy alignments. Dependence on the mass and the large-scale environment
• Joint Modelling of Astrophysical Systematics for Cosmology with LSST Cosmic Shear
• Accurate dark matter halo elongation from weak-lensing stacking analysis
• Mock Observations: Three Different Types of Galaxy Alignment in TNG100 Simulations
• Intrinsic alignments of the extended radio continuum emission of galaxies in the EAGLE simulations
• Probabilistic Estimators of Lagrangian Shape Biases: Universal Relations and Physical Insights
• Information content in anisotropic cosmological fields: Impact of different multipole expansion scheme for galaxy density and ellipticity correlations
• Alignment between Satellite and Central Galaxies in the EAGLE Simulation: Dependence on the Large-Scale Environments
• Statistical exploration of halo anisotropic clustering and intrinsic alignments with the mass-Peak Patch algorithm
• Testing extensions to LCDM on small scales with forthcoming cosmic shear surveys
• Redshift and stellar mass dependence of intrinsic shapes of disc-dominated galaxies from COSMOS observations below $z=1.0$
• Intrinsic and extrinsic gravitational flexions
• Deep lensing with a twist: E and B modes in a field with multiple lenses
• Simulation budgeting for hybrid effective field theories
• Etherington duality breaking: gravitational lensing in non-metric spacetimes versus intrinsic alignments
• A direct detection method of galaxy intrinsic ellipticity-gravitational shear correlation in non-linear regimes using self-calibration
• Parity Violation in Galaxy Shapes: Primordial Non-Gaussianity
• Galaxy-halo internal alignments across cosmic time
• An anti-correlation between barycentre offsets and velocity dispersion for highest overdensity subhalos in cosmological simulations
• Intrinsic alignments of galaxies in multiple projections
• Shape, alignment, and mass distribution of baryonic and dark-matter halos in one EAGLE simulation
• Non-linear infusion of intrinsic alignment and source clustering: impact on non-Gaussian cosmic shear statistics